1. Field of the Invention
The present general inventive concept relates to an aligning apparatus, and more particularly to, an aligning apparatus to align a substrate and a print head so that the print head can perform a printing operation on the substrate.
2. Description of the Related Art
Generally, display panels to display images are formed on flat display apparatuses such as thin film transistor-liquid crystal displays (TFT-LCD) and organic electro luminescence displays (ELD).
A process of manufacturing a display panel includes a printing process to form a color filter on a display panel substrate. Inkjet printing devices have been widely used to perform this printing process.
An inkjet printing device includes a print head having a plurality of orifices. The print head ejects ink for the color filter from the orifices onto the display panel substrate. The ink is then cured on a plurality of pixels formed on the display panel substrate. Using the inkjet printing device to perform this printing process is advantageous, since the inkjet printing device is less expensive and simpler than conventional photolithography devices.
The inkjet printing device is typically used with an aligning apparatus to align the print head with the display panel substrate so as to allow ink to be ejected onto the pixels of the display panel substrate or an inspecting apparatus to inspect whether the ink is properly positioned on the pixels of the display panel substrate in order to aid in the printing process.
The aligning apparatus aligns the print head and the pixels of the display panel substrate before the print head ejects the ink onto the pixels of the display panel substrate. As a result, cost can be decreased by reducing the manufacturing processes, since it becomes unnecessary to inspect the positions of the ink after the ink is ejected onto the display panel substrate.
A conventional inkjet aligning apparatus to manufacture this kind of display panel is disclosed in Korean Patent Application No. 10-2002-0018970. The conventional aligning apparatus for manufacturing the display panel comprises a head capable of aligning multiple orifices, and multiple charge coupled device (CCD) cameras controlling the head so that each orifice is properly positioned on grids drawn adaptively according to pixel pitches of a pattern of the display panel substrate. Printing is then performed using the head.
A CCD camera may be provided on a lower side of a stage that supports a transparent display panel substrate. With this CCD camera, the display panel substrate may be photographed from underneath, and positions of the orifices can be photographed through the transparent display panel substrate. Accordingly, while using images photographed by the CCD camera, the orifices may be aligned on the grid drawn adaptively according to the pixel pitches of the display panel substrate pattern.
However, because the conventional aligning apparatus for manufacturing the display panel is provided on the lower side of the stage supporting the display panel substrate, and the display panel substrate and the orifices are photographed through holes formed on the stage, camera mounting is difficult, and the structure of the aligning apparatus is complicated.
In addition, the conventional aligning apparatus for manufacturing the display panel photographs orifices through the transparent display panel substrate. In the course of transmitting images and photographing the transparent display panel substrate, the images of the orifices may be distorted due to refraction and the like, thus making it difficult to control the distortion of the images.
Further, the conventional aligning apparatus for manufacturing the display panel is typically only used for transparent display panel substrates, thus it can not be used with opaque substrates.